Receive

Command Code

This field must contain 0x60 to execute the Receive IOPB.

Command Options

Table 3-33. Command Options

Command Options

Offst

15

14

13

12

11

10

9

8

7

6

 

5

4

3

2

1

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0x01

AN

 

 

 

 

 

 

 

DMC

 

PORT

 

 

RSV

RSV

IE

 

Y

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Interrupt enable

As defined in the Common IOPB Structures section.

Port selector

This field specifies the port to which the receive resources will be allocated. Valid ports range from 0 to 3.

Disable multiple completion (DMC)

Setting this bit prevents a returned frame from being returned using the multiple completion mechanism.

Non-port designated (ANY)

Setting this bit allows the receive resources specified in the command to be used for any port with incoming traffic.

Buffer Address

This field contains the host VMEbus physical address for the start of the incoming data.

Maximum / Actual Transfer Size

When supplied by the host to the controller this field contains the maximum amount of data that can be transferred to the specified location. This should be no smaller than the largest frame expected to be received, which for Ethernet normally is 1518 bytes. When the controller returns this command for a received frame, this field will contain the actual amount of data transferred, plus 4. Thus, a received frame of 64 bytes have 68 as the value returned in this field.

Packet Type / Length Field

When a particular MAC is placed in certain monitor modes, network traffic may be reported to the host without any actual frame data being transferred. In this case, this field contains the Message Type frame header when operating on an Ethernet compatible network, and the Length Field on an 802.3 network.

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